Impact of zinc oxide nanoparticles on the bio-productivity, seed quality and biochemical properties of Arachis hypogaea (L.)

Abstract

Zinc oxide nanoparticles (ZnO-NPs) offer improved nutrient delivery, although their optimum concentrations and impact on groundnut crops remain unclear. This study investigated the impact of zinc oxide nanoparticle (ZnO-NPs) concentrations on the growth performance, yield, and biochemical properties of Arachis hypogaea L. (groundnut).  The concentrations of ZnO-NP investigated were 0.00 (control), 0.25, 0.50, 0.75, 1.00 and 1.25 g/L. The ZnO-NPs synthesized by the direct precipitation method had FTIR that peaks at 455.22 cm^-1 and 1384.94 cm^-1, corresponding to Zn-O stretching and deformation vibration. The rod-flower shape of ZnO-NP had a particle size of < 0.99 with good purity. The synthesized ZnO-NPs significantly increased (p<0.05) percentage seed germination that ranged from 66.67% at 0.25 g/l to 97.67 at 1.25 g/L when compared with the control (56.65%). All ZnO-NP treatments enhanced morphological growth characters and yield attributes when compared with the control. However, chlorophyll content under ZnO-NPs were at par with the control. Nitrate reductase and carbonic anhydrase enzymes increased with the increase in the concentrations of nanoparticles. Seed quality in terms of mineral and proximate compositions showed inconsistent trends. However, Zn and other mineral elements such as K Mg, P and Na were significantly higher under ZnO-NPs when compared with the control. Similarly, ZnO-NPs limit fat accumulation in seeds but showed marked influence on   ash, fibre, protein, carbohydrate and energy values. It can be concluded that groundnut bio-productivity, biochemical attributes and seed quality were generally enhanced by zinc oxide nanoparticles with doses between 0.75 and 1.25 g/L showing the most profound effects.